Temperature dependence of EXAFS in amorphous arsenic

EXAFS measurements at different temperatures on amorphous arsenic are reported. The low values of the EXAFS mean square relative displacement σ² for the first coordination shell are consistent with a distribution of As₄ pyramidal units throughout the amorphous network, giving a locally very ordered first shell, whose disorder is essentially dynamic in character. The temperature dependence of the vibrational contribution to the EXAFS Debye-Waller factor is well described by an Einstein oscillator model.